"Maybe it's just a Bostonian thing, but I was really, just genuinely pissed off that someone would ruin such a celebratory day and a historical moment," Flanagan said at the start of the segment. "It was a personal attack on my city."

Between clips of her gliding along a snow-covered Boston race course, the segment dove into the hometown pride Flanagan has for the marathon and her unwavering desire to break the tape. Growing up in nearby Marblehead, Massachusetts, with two world-caliber runners for parents, Flanagan said, "I thought everyone got up and went to the 'Church of the Sunday Long Run.'" Then she explained how the countless Patriot's Day's spent spectating on Hereford and Boylston Street inspired her to lace up herself.

"It's my ultimate dream and goal to win the Boston Marathon," Flanagan said. "I am all in with this training."

Host Anderson Cooper spoke with new Boston Police Commissioner William Evans, who ran the Boston Marathon last year before leading the manhunt that ensued after the attack, and Tom Grilk, the executive director of the Boston Athletic Association. Both echoed the sentiment that Marathon Monday will be the celebration it always has been.

"To have just come down that street an hour earlier with such excitement, such joy, and then to return again...I just couldn't believe that that had happened on Boylston Street," Evans told Cooper in the interview. "You're going to see 36,000 people on that course with the same principle: Let's prove that we won't be intimidated by what happened back in April."

Later in the 13-minute video, viewers got a behind-the-scenes look at Flanagan's "full-time job," showing her training on the trails in her now hometown of Portland, Oregon.

Then Cooper literally followed in her footsteps, "racing" Flanagan over 400 meters at her marathon race pace. Cooper, who took off sprinting, quickly fell behind Flanagan who laughed from start to finish. "Did you hear those giggles?" Flanagan asked a panting Cooper. "That was pure joy." The bit put into perspective just how fast elites like Flanagan can run 26.2 miles.

After showing a clip of Flanagan's second-place finish at the 2010 New York City Marathon, her coach, Jerry Schumacher, explained why he thinks she's ready to win.

"[New York showed] she can run the 26 miles, she can do the training for it," Schumacher said. "In the right kind of race, she'll definitely be dangerous."

Last year, Flanagan finished fourth at the Boston Marathon, a place she hopes to improve upon April 21.

When Cooper asked Evans what it would mean if an American woman won Boston, he said, "It would be super. It would show how resilient this community is and how hard someone would train to make sure this was special for everyone. We'll go crazy."